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CVE-2021-32837

mechanize vulnerable to ReDoS

7.5 HighFix available

mechanize, a library for automatically interacting with HTTP web servers, contains a regular expression that is vulnerable to regular expression denial of service (ReDoS) prior to version 0.4.6. If a web server responds in a malicious way, then mechanize could crash. Version 0.4.6 has a patch for the issue.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
High

Exploit likelihood

28.7%Up 27.6 points since Jan 18, 2023
90%50%10%1%

What each source reports

CVE List Score used 7.5

mechanize vulnerable to ReDoS

mechanize, a library for automatically interacting with HTTP web servers, contains a regular expression that is vulnerable to regular expression denial of service (ReDoS) prior to version 0.4.6. If a web server responds in a malicious way, then mechanize could crash. Version 0.4.6 has a patch for the issue.

Record
CVE-2021-32837
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-1333
Updated
2026-11-02
EUVDEUVD-2023-0144 7.5

mechanize, a library for automatically interacting with HTTP web servers, contains a regular expression that is vulnerable to regular expression denial of service (ReDoS) prior to version 0.4.6. If a web server responds in a malicious way, then mechanize could crash. Version 0.4.6 has a patch for the issue.

Record
EUVD-2023-0144
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
GitHub AdvisoriesGHSA-g3pv-pj5f-3hfq 8.7

mechanize Regular Expression Denial of Service vulnerability

mechanize, a library for automatically interacting with HTTP web servers, contains a regular expression that is vulnerable to regular expression denial of service (ReDoS) prior to version 0.4.6. If a web server responds in a malicious way, then mechanize could crash. Version 0.4.6 has a patch for the issue.

Record
GHSA-g3pv-pj5f-3hfq
CVSS 4.0
8.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-1333
Updated
2026-11-02
NVD 7.5

mechanize, a library for automatically interacting with HTTP web servers, contains a regular expression that is vulnerable to regular expression denial of service (ReDoS) prior to version 0.4.6. If a web server responds in a malicious way, then mechanize could crash. Version 0.4.6 has a patch for the issue.

Record
CVE-2021-32837
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-1333
Updated
2026-11-02
OSV 7.5

mechanize, a library for automatically interacting with HTTP web servers, contains a regular expression that is vulnerable to regular expression denial of service (ReDoS) prior to version 0.4.6. If a web server responds in a malicious way, then mechanize could crash. Version 0.4.6 has a patch for the issue.

Record
CVE-2021-32837
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVDEBIAN-CVE-2021-32837 7.5

mechanize, a library for automatically interacting with HTTP web servers, contains a regular expression that is vulnerable to regular expression denial of service (ReDoS) prior to version 0.4.6. If a web server responds in a malicious way, then mechanize could crash. Version 0.4.6 has a patch for the issue.

Record
DEBIAN-CVE-2021-32837
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
Show 7 moreShow less
OSVGHSA-g3pv-pj5f-3hfq 8.7

mechanize Regular Expression Denial of Service vulnerability

mechanize, a library for automatically interacting with HTTP web servers, contains a regular expression that is vulnerable to regular expression denial of service (ReDoS) prior to version 0.4.6. If a web server responds in a malicious way, then mechanize could crash. Version 0.4.6 has a patch for the issue.

Record
GHSA-g3pv-pj5f-3hfq
CVSS 4.0
8.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-1333
Updated
2026-11-02
OSVUBUNTU-CVE-2021-32837 7.5

mechanize, a library for automatically interacting with HTTP web servers, contains a regular expression that is vulnerable to regular expression denial of service (ReDoS) prior to version 0.4.6. If a web server responds in a malicious way, then mechanize could crash. Version 0.4.6 has a patch for the issue.

Record
UBUNTU-CVE-2021-32837
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVMGASA-2023-0036 No score

Updated python-mechanize packages fix security vulnerability

Denial of service via crafted regular expression (CVE-2021-32837) Fixed mechanize not found during build.

Record
MGASA-2023-0036
Updated
2026-11-02
OSVopenSUSE-SU-2023:0030-1 No score

Security update for python-mechanize

This update for python-mechanize fixes the following issues:

Update to version 0.4.8:

  • CVE-2021-32837: Fixed a denial of service via regular expression (boo#1207242).
  • Fixed mechanize not found during build (boo#1202003).
Record
openSUSE-SU-2023:0030-1
Updated
2026-11-02
OSVopenSUSE-SU-2024:12621-1 No score

python310-mechanize-0.4.8-4.1 on GA media

These are all security issues fixed in the python310-mechanize-0.4.8-4.1 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2024:12621-1
Updated
2026-11-02
OSVopenSUSE-SU-2025:15098-1 No score

python311-mechanize-0.4.10-1.4 on GA media

These are all security issues fixed in the python311-mechanize-0.4.10-1.4 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2025:15098-1
Updated
2026-11-02
OSVPYSEC-2023-25 No score

mechanize, a library for automatically interacting with HTTP web servers, contains a regular expression that is vulnerable to regular expression denial of service (ReDoS) prior to version 0.4.6. If a web server responds in a malicious way, then mechanize could crash. Version 0.4.6 has a patch for the issue.

Record
PYSEC-2023-25
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
mechanize
PyPI
 before 0.4.6
0.4.6
python-mechanize
Debian:12
 before 1:0.4.7-1
1:0.4.7-1
python-mechanize
Debian:13
 before 1:0.4.7-1
1:0.4.7-1
python-mechanize
Debian:14
 before 1:0.4.7-1
1:0.4.7-1
python-mechanize
Debian:10
 before 1:0.2.5-3+deb10u1, plus listed versions
1:0.2.5-3
1:0.2.5-3+deb10u1
python-mechanize
Debian:11
 before 1:0.4.5-2+deb11u1, plus listed versions
1:0.4.5-2
1:0.4.5-2+deb11u1
mechanize
PyPI
 before 0.4.6, plus listed versions
0.0.10a0.0.11a0.0.1a0.0.8a0.0.9a
Show 31 moreShow less
0.1.0a0.1.100.1.110.1.1a0.1.2b0.1.4b0.1.5b0.1.6b0.1.7b0.1.80.1.90.2.00.2.10.2.20.2.30.2.40.2.50.3.00.3.10.3.20.3.30.3.40.3.50.3.60.3.70.4.00.4.10.4.20.4.30.4.40.4.5
0.4.6
python-mechanize
Mageia:8
 before 0.4.6-1.mga8
0.4.6-1.mga8
mechanize
PyPI
 before 0.4.6, plus listed versions
0.0.10a0.0.11a0.0.1a0.0.8a0.0.9a
Show 45 moreShow less
0.1.0a0.1.100.1.110.1.1a0.1.2b0.1.4b0.1.5b0.1.6b0.1.7b0.1.80.1.90.2.00.2.10.2.20.2.30.2.40.2.50.3.00.3.10.3.20.3.30.3.40.3.50.3.60.3.70.4.00.4.10.4.20.4.30.4.40.4.5v0.4.5v0.4.4v0.4.3v0.4.2v0.4.1v0.4.0v0.3.7v0.3.6v0.3.5v0.3.4v0.3.3v0.3.2v0.3.1v0.3.0
0.4.6
python-mechanize
Ubuntu:16.04:LTS
 All versions, plus listed versions
1:0.2.5-3
 None known
Show 5 moreShow less
Affected packages
PackageAffectedFixed
python-mechanize
Ubuntu:18.04:LTS
 All versions, plus listed versions
1:0.2.5-3
 None known
python-mechanize
Ubuntu:20.04:LTS
 All versions, plus listed versions
1:0.2.5-31:0.4.3-21:0.4.5-11:0.4.5-2
 None known
python-mechanize
SUSE:Package Hub 15 SP4
 before 0.4.8-bp154.2.3.1
0.4.8-bp154.2.3.1
python-mechanize
openSUSE:Leap 15.4
 before 0.4.8-bp154.2.3.1
0.4.8-bp154.2.3.1
python-mechanize
openSUSE:Tumbleweed
 before 0.4.10-1.4
0.4.10-1.4

History

History
RecordedChangedSources
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-32837 is a high vulnerability (CVSS 7.5) in Mechanize Project Mechanize, published January 17, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 28.7%, the 98th percentile. Fixed in mechanize 0.4.6.

References

Show 14 moreShow less
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